[Arie]

A character will be marked missing that if during the sweep the high ranks have to do [activity see] they've not posted within that period. It is usually a 2 week period and if the cat is placed in missing then they'll have to go through rejoining to be allowed back
The sweep happens every 2 weeks and its all cats on the current allegiances that are being checked if they've posted. Different clans have different requirements such as 1-3 posts within the 2 week period.

I.e for WC the next sweep will cover the 1st of Jan - 15th of Jan. So to be safe, the character must have posted at least once during that period.
[ @littlefox ]